This invention relates generally to piercing specimen collection containers in an automated hematology analyzer. More particularly, the invention is directed to a universal stripper plate for a hematology analyzer which can accept a plurality of different sizes and types of collection containers.
Automated blood and blood cell analyzers are well known. These analyzers typically utilize a portion of a whole or pre-prepared blood sample. When the blood sample is taken from a subject, it usually is placed into a collection container such as a vial or test tube. With the potential of exposure to highly infectious diseases by an operator, such as the HIV virus or hepatitis, the tube is closed, typically by a rubber stopper. Many types of blood sample sampling devices have been developed, generally following the procedure of piercing the tube stopper to aspirate a portion of the blood sample. The needle probe or cannula then is removed from the tube and the stopper maintains the remainder of the blood sample sealed in the tube.
In automated hematology analyzers, such as a STKS hematology analyzer sold by the assignee of the present invention, Coulter Corporation of Miami, Fla., a plurality of the sample collection containers or tubes are placed into a tube carrier or cassette. The cassette then is loaded into the hematology analyzer and moved to an aspiration location. Each tube individually is moved to the aspiration location and pierced through its stopper by a transfer needle and a portion of the sample removed for analysis in the hematology analyzer.
Currently, there are four major types of tubes, each of which has a different size and shape. Alignment of each tube in the aspiration location is verified by a tube sensor or detector. One self-adjusting tube detector which preferably can be utilized in a accordance with the present invention is disclosed in U.S. Ser. No. 08/250,264, entitled "Self-Adjusting Tube Detector", filed concurrently herewith and incorporated herein by reference. At the aspiration location, the hematology analyzer includes a stripper plate which functions to align and seat the tube and stopper for piercing by the transfer needle. Currently, this requires four different stripper plates, one for each type of tube. Further, only one type of tube can be operated on by the respective stripper plates, requiring the cassette to be loaded with only the single corresponding type of tube.
When it is desired to utilize another type of tube, the stripper plate has to be changed to the stripper plate corresponding to the other type of tube. This is not an operator operation, but requires a maintenance type procedure to ensure the stripper plate is mounted and is operating correctly.
It therefore would be desirable to provide a universal stripper plate which can accommodate any of the various types of tubes and which allows full flexibility in handling the different tubes in the hematology analyzer.